The present invention relates to couplings in general, and more particularly to improvements in coupling devices which can be used with advantage in photographic developing and like machines. Still more particularly, the invention relates to improvements in coupling devices which can be used to transmit torque from a first transporting unit to a second transporting unit in the vessel containing a developing solution, a fixing bath, a rinsing bath, a gaseous drying fluid and/or other media which are to treat continuous webs or discrete sheets of photosensitive material, such as photographic films, photographic paper, exposed film which issues from a photocomposing machine, or the like.
German Pat. No. 14 97 395 discloses a developing machine which can treat roll films of predetermined width. The machine comprises a series of tanks each of which contains a different fluid. The patented developing machine further comprises film transporting units in the form of so-called racks having a width corresponding to the width of films which are to be treated in the machine. The racks are removably inserted into the tanks and are disposed one after the other so that successive increments of a film advance through successive baths by advancing along paths which are defined by the racks in the respective tanks. Each of the racks is provided with a discrete drive which can receive motion from a central driving unit of the developing machine. The width of each rack corresponds to that which is needed to treat roll films of maximum width (105 mm) presently available on the market and demanded by the users of films. The very wide films are used in X-ray laboratories of private physicians, hospitals, nursing homes and similar institutions. However, the trend in X-ray laboratories is toward the use of narrower roll films, namely, 35 mm or 16 mm film, due to transition from the taking of still pictures to the making of motion pictures. In addition to 35 mm or 16 mm film, an X-ray laboratory is likely to use also films having a width of 100, 90 or 70 mm. In certain other branches, such as in the fields where information is stored on microfilm, the customary film widths are 8, 16 and 35 mm. The same holds true for amateur photography.
The processing of each type of film (i.e., of each film having a given width) necessitates the use of a different set of racks. This is necessary in order to ensure adequate guidance of films through successive treating stations in a developing machine. Another problem which is encountered in conventional developing machines is that the establishment of connections between a central driving unit and the driving units of discrete racks takes up much time and that such connections are complex, costly and sensitive. Moreover, proper connections can be established only by resorting to parts which are produced with a high degree of precision and only if the racks are installed in the respective tanks with a high or very high degree of accuracy. Still further, the patented developing machine is not designed for simultaneous treatment of wider, narrower, highly sensitive and less sensitive films, photographic paper or like photosensitive materials.
Commonly owned copending U.S. patent application Ser. No. 372,102, filed Apr. 27, 1982 now U.S. Pat. No. 4,416,529 granted Nov. 22, 1983 by Alfons Kastl, discloses a developing machine which is capable of simultaneously processing several films each of which has a different width, some of which have different widths or all of which have the same width. The machine which is disclosed in the application Ser. No. 372,102 employs racks of different widths which can be placed one next to the other and whose mobile parts can receive motion from a common driver unit in such a way that the common driver unit transmits torque to an input element of a first rack, an output element of the first rack transmits torque to the input element of the neighboring rack, and so forth. To this end, the machine of the application Ser. No. 372,102 employs special coupling devices each of which is designed to separably couple a shaft in a first rack to a shaft in the neighboring second rack. It has been found that, in addition to numerous important advantages, the coupling devices which are used in the machine of the application Ser. No. 372,102, also exhibit a drawback, namely, they do not permit for movement of neighboring racks at right angles to the axes of the aforementioned shafts, i.e., the placing of racks next to each other necessitates the movement of one rack toward the other rack in the direction of the axes of shafts which are to be coupled to each other. This entails that the compartments of a single tank or the compartments of discrete tanks cannot be filled to capacity, i.e., each compartment must leave room for movement of the last-inserted rack away from the neighboring rack in order to allow for separation of such neighboring racks from each other.